Feeds for Production of Market-sized Cutthroat Technical Report western regional aquaculture center

Gary Fornshell, University of Christopher Myrick, State University Madison Powell, University of Idaho Wendy Sealey, Fish and Wildlife Service

United States Department of Agriculture National Institute of Food and Agriculture 1 PROJECT PARTICIPANTS

Christopher Myrick, Colorado State University Cheyenne Owens, Colorado State University Biswamitra Patro, University of Idaho Madison Powell, University of Idaho Pat Blaufuss, University of Idaho Tracy Kennedy, University of Idaho Wendy Sealey, United States Fish and Wildlife Service Brian Ham, United States Fish and Wildlife Service Gary Fornshell, University of Idaho Jeremy Liley, Liley Fisheries, Inc. David Brock, Rangen, Inc. Jackie Zimmerman, Skretting USA Rick Barrows, Aquatic Feed Technologies, LLC

Photo credits: Cover: Gary Fornshell Above: iStock.com/KaraGrubis 2 Table of Contents

Introduction: Why Consider ? 1 Snake Cutthroat Trout—A Culturable Cutthroat 2 Is Raising Fish for the Recreational Market Worthwhile? 3 Overcoming Challenges to Raising Cutthroat Trout 3 Fish Nutrition 101—A Primer on Feed Formulation 3 Feed Pellet Texture Matters 5 Cutthroat Trout Growth—Does It Match ? 5 Thermal Growth Coefficient 5 Comparing Rainbow and Cutthroat Trout Performance 6 Suggested Readings 10 Acknowledgments 11

Figures 1. cutthroat trout. 1 2. Map showing the distribution of extant cutthroat trout 2 in the western United States. 3. Juvenile Snake River cutthroat trout ready for stocking. 3 4. Classic bell-shaped growth-temperature curve. 6 5. Sigmoid growth curve. Based on Management, Second Edition, Gary Wedemeyer, editor 7 6. Market-size Snake River cutthroat trout. 8 7. Growth of Snake River cutthroat trout under production conditions fed two diets. Data points indicate sampling dates. 9 8. Female Snake River cutthroat trout. 10

Tables 1. The two major groups of amino acids. 4 2. Experimental cutthroat trout feed formulation (as-fed basis). 8 3. Calculated constituent values of experimental feed formulation. 9 4. Proximate composition of the diets. 10

Box 1. Calculating Thermal Growth Coefficient 7

3 Photo credit: Wendy Sealey

4 Introduction: Why Consider Cutthroat Trout? Cutthroat trout ( clarkii) are popular game . Other subspecies of cutthroat trout are adfluvial, fish in the western United States, prized for their brilliant living in large and migrating into to spawn, coloration (Figure 1). For commercial fish farmers, these and still others reside in rivers and streams year-round. colorful trout potentially represent a valuable high-end Cutthroat trout also vary widely in size. One lineage of specialty product for the recreational stocking market currently stocked in Pyramid because of their limited supply compared to the more , , grows to more than 40 pounds, while some commonly grown rainbow trout (Oncorhynchus mykiss). varieties found in small headwater streams rarely exceed There are a variety of cutthroat trout O.( clarkii) subspecies two pounds. in the western U.S., including at least 11 distinct strains, Despite the wide range of fish sizes and habitats, of which about nine were still present in 1992 (Figure 2) cutthroat trout subspecies share some key characteristics Historical distribution included temperate rainforests of that should be of interest to fish culturists. the , pluvial lakes within the , • Cutthroat trout are generally spring spawners, a trait subalpine areas of the , and high deserts that can increase the likelihood of hybridization with of the Southwest. Inland cutthroat trout have adapted to a most strains of the closely related rainbow trout. diverse range of habitats and are found in tiny headwater • Their natural diet consists mostly of aquatic and streams as well as large rivers and large lakes, such as Lake terrestrial insects and other aquatic invertebrates. Tahoe on the –Nevada border and Larger individuals will eat fish. in Nevada. • Because they are closely related to the rainbow trout, As a result of adapting to diverse habitats, cutthroat cutthroat trout readily interbreed to produce cuttbows, trout display a varied set of life history strategies, a cross that can sometimes breed successfully. paralleling those seen in the closely related rainbow This propensity to hybridize with rainbow trout is one trout. Some, like the are similar to of the reasons cutthroat trout declined throughout anadromous , rearing in freshwater as juveniles, their native range following the introduction of migrating into the ocean, and returning to freshwater to rainbow trout.

Photo credit: Gary Fornshell Figure 1. Snake River cutthroat trout.

1 • Cutthroat trout, similar to other salmonids, build and as a pure cutthroat trout or more commonly, as a cuttbow. lay their eggs in redds, typically in the gravel The Snake River cutthroat is a popular sportfish, renowned of streams, rivers, or the inlets and outlets of ponds for its willingness to aggressively strike dry and small and lakes. Egg incubation time varies with water lures. Fisheries management agencies favor the Snake temperature. River cutthroat because it can be readily distinguished • All cutthroat trout subspecies are excellent sportfish, from other native cutthroat subspecies by its distinct fine- taking flies, lures, and bait. They are often prized by spotted coloration. anglers for their coloration and vigorous fighting Compared to the other cutthroat trout subspecies, ability. the Snake River cutthroat trout is are well suited for commercial aquaculture due to faster growth and better Snake River Cutthroat Trout— feed conversion efficiency. This strain is often approved A Culturable Cutthroat for private aquaculture production and stocking, unlike The Snake River cutthroat trout, a subspecies originally many of the other, rarer, cutthroat subspecies (Figure 3). found in the Snake River drainage, is of particular interest State agencies that regulate aquaculture and the stocking to fish culturists. Its distribution is not shown in Figure 2 of sport fish vary from state to state, as do the nature of because it is the most widely introduced subspecies and the regulations. Consult your state departments of natural has been distributed throughout the western states either resources or agriculture to determine which species are

WA

MT 10 1 1 Coastal OR ID 2 Rio Grande 11 3 Greenback 7 8 WY 4 6 5 Lahontan 5 9 4 6 Humboldt NV UT 3 CA 7 Alvord CO 8 Whitehorse

Bonneville 2 9 10 Westslope AZ 11 Yellowstone NM

Figure 2. Map showing the distribution of extant cutthroat trout subspecies in the western United States. Data are from Behnke 1992. The Snake River cutthroat has been widely introduced and is not shown on this map.

2 Photo credit: Gary Fornshell Figure 3. Juvenile Snake River cutthroat trout ready for stocking.

approved for propagation, particularly when working with aquaculture industry sales generates $36 in economic cutthroat trout. There are a number of rare subspecies activity, and every million dollars of sales generates that may be subject to special regulations. Alternatively, 500 jobs. contact your state’s extension service for assistance and information. Ultimately, any producer needs to consider Overcoming Challenges to Raising the unique local regulatory environment and economic Cutthroat Trout situation before electing to raise cutthroat trout for the A previous Western Regional Aquaculture Center recreational market. (WRAC) research project evaluated factors limiting consistent growth, survival, and quality from year to year Is Raising Fish for the Recreational of fry and fingerling cutthroat trout production. That Market Worthwhile? project focused on evaluating commercial rainbow trout While the scale of operations that produce trout for the feeds and open-formula experimental feeds, determining recreational market is small compared to that of the fish optimum water temperature and fish rearing density for farms that produce trout for the food market, the economic the best growth. One finding from that study was that contribution of the recreational-based aquaculture sector cutthroat trout were more sensitive to feed ingredients in the western U.S. is substantial. In 2010, about 173 and required different ingredient combinations than the producers of fish for the recreational market generated closely related rainbow trout. $53.2 million in direct annual sales and over 1200 jobs. Their customers included private pond owners, dude Fish Nutrition 101— ranches, fishing clubs, homeowners’ associations, fee- A Primer on Feed Formulation fishing operations, and public waters. The average angler Fish feed typically represents 50% or more of production spent $150 per day at these businesses. In the western costs. Selecting the correct feed is essential for producing U.S., the total annual economic contribution of the aquatic economically. Developing cost-effective, recreational-based aquaculture industry was estimated nutritious diets for fish requires incorporating knowledge to be $1.9 billion. Accounting for both forward and of species-specific nutritional requirements into balanced backward linkages, every dollar of recreation-based nutrient-based feeds that are delivered using appropriate

3 feeding methods and rates. The basic building blocks of Lipids are organic substances that include fats and a feed consist of proteins (amino acids), lipids (fats), carbo- oils. They are the most concentrated energy source of the hydrates (sugars and starches), vitamins, and minerals. nutrient groups, containing about twice as much energy Fish metabolize proteins, lipids, and carbohydrates to per unit weight as protein or carbohydrates. Dietary lipids produce energy required for numerous physiological also supply essential fatty acids and serve as transporters processes and physical activities, and they require certain for fat-soluble vitamins. Fatty acids include saturated fatty vitamins and minerals in small quantities to maintain acids (no double bonds), polyunsaturated fatty acids good health. (> 2 double bonds), and highly unsaturated fatty acids Proteins consist of various amino acids. Although (> 4 double bonds). Fatty acids of the linolenic acid over 200 amino acids are found in nature, only about 20 (omega-3) family are considered more essential than those are common. Amino acids are grouped into essential of the linoleic acid (omega-6) family. Marine fish oil is high (indispensable) and nonessential (dispensable) amino acids in omega-3 unsaturated fatty acids and is a good source (Table 1). Fish require the same 10 essential amino acids of lipids for fish feeds. The trend in recent years is to use that other vertebrates, including humans, require. It is higher levels of lipids in feeds for salmon and trout. important to meet a fish’s minimum dietary requirement Increasing dietary lipid levels can help reduce the cost of for protein, with a balanced mixture of amino acids, to feed by sparing protein; however, too high a level can result ensure adequate growth and health of the fish. Fish fed in excessive fat deposition in the liver, decreasing fish diets deficient in any one of the essential amino acids health, product quality, and product shelf life. become inactive and lose both appetite and weight. Fish do not have a specific dietary requirement for However, feeding dietary protein to excess is wasteful carbohydrates, but because carbohydrates are the least because protein is the most expensive dietary component. expensive source of energy for fish feeds, they are included Additionally, excess dietary protein increases excretion of in fish feeds to reduce feed costs and to provide pellet nitrogenous waste, leading to water quality issues. Protein integrity and stability. Carnivorous fish, such as trout, requirements for herbivorous and omnivorous fish utilize dietary carbohydrate for energy less efficiently than typically range from 25 to 35 percent crude protein. Trout herbivorous and omnivorous fish such as tilapia. Dietary and other carnivorous species may require 40 to 50 percent carbohydrate is stored as glycogen in liver and muscle, crude protein, depending upon species and life stage. where it is readily available to meet energy demands. Some dietary carbohydrate is also converted to fat and stored in the body for energy. Table 1. The two major groups of amino acids. Vitamins are organic compounds required in relatively small concentrations in the diet to support normal fish growth and health. Vitamins can be classified as water- ESSENTIAL NON-ESSENTIAL soluble and fat-soluble. Water-soluble vitamins include B Arginine Alanine vitamins, choline, inositol, and ascorbic acid (vitamin C). Histidine Asparagine Vitamin C is an antioxidant, and it boosts the immune Isoleucine Aspartic acid system of fish. Fat-soluble vitamins include vitamins A, D, E, and K. Water-soluble vitamins are not stored in Leucine Cystine large amounts in the body. Signs of deficiency occur Lysine Glutamic acid much sooner than with fat-soluble vitamins, which are Methionine Glutamine metabolized and stored with body lipids. Vitamin Phenylalanine Glycine deficiencies are seldom observed in commercial Threonine Proline aquaculture production because relatively inexpensive Tryptophan Serine vitamin premixes are added to the feed. Excess vitamins Valine Tyrosine are added to the feed to ensure adequate nutrition and mitigate potential losses of vitamins during feed manufacture and storage.

4 Minerals are inorganic elements required in the diet Thermal Growth Coefficient for normal body functions. Fish require the same minerals The thermal growth coefficient (TGC) is a growth rate as other vertebrates. Minerals can be classified as macro formula based on a presumption of body weight as or micro, based on the quantities required in the diet and approximately equal to the cube of the fish’s length stored in the body. Fish can also absorb dissolved minerals (W ~ L3) that incorporates time and water temperature. from the water, allowing them to meet some of their This formula allows for a better comparison of growth metabolic requirements in case of mineral deficiencies in rates for salmonids than other growth rate formulas over their diet. Common dietary macrominerals are calcium, time and between different farms because it takes into phosphorus, magnesium, chloride, sodium, potassium, account water temperature. Experimentally, the thermal and sulfur. These minerals are involved with osmo- growth coefficient formula has closely followed the actual regulation, acid-base balance, and bone formation and growth curves of rainbow trout, , Atlantic integrity. Microminerals (or trace minerals) include iron, salmon, , and . However, as copper, chromium, cobalt, iodine, manganese, zinc, and with any growth-rate formula, one should be aware of selenium. Microminerals are required in small amounts the assumptions the formula is based upon and that as components in enzyme and hormone systems. uncritical use can lead to mistaken growth projections. Previous work with cutthroat trout identified the lack The assumptions of the TGC formula are: of specific feeds as one factor limiting growth of fry and • growth increases in a steady and predictable manner fingerlings. There is also a need to develop or identify with increasing water temperature suitable feeds (e.g., those being produced for other salmon • growth in length (for any temperature) is constant or trout species) for production of market-sized cutthroat over time trout. • the weight to length relationship is W ~ L3 Growth does not show a steady increase with increasing Feed Pellet Texture Matters water temperature, but instead shows the classic bell- Feed characteristics such as buoyancy and texture affect shaped curve (Figure 4), where growth rates are lower with feed acceptance in some fish, including cutthroat trout. lower water temperatures, increase as water temperature There were no differences in growth rate, feed conversion approaches the growth optimum, and then decline as ratio, feed intake, and survival when Snake River cutthroat water temperature exceeds the optimum. A TGC calculated trout were fed the same feed formulation either as float- for a specific water temperature should not be used for ing or sinking extruded pellets. However, when fed the growth projections over the entire range of temperatures same formulation manufactured as a semi-moist pellet, included on the growth-temperature curve. The use of Snake River cutthroat trout gained more weight compared TGC to predict growth works best for water temperatures to those fed sinking and floating pellets. It has yet to be that are on the ascending curve of the growth-temperature determined if the benefit in weight gain by Snake River curve. Fish growth in length is not constant under the full cutthroat fed semi-moist pellets is enough to justify the range of conditions over which farmed fish may be reared; use of this more expensive feed, which requires special however, in general, salmonid growth in length is constant temperature-controlled storage and adds to production between water temperatures of 5 and 15°C. and transportation costs. The formula for thermal growth coefficient is:

Cutthroat Trout Growth— 1/3 1/3 • TGC = [(WF – WI ) / Σ(t x °C] x 100 Does It Match Rainbow Trout? where W and W are the final and initial fish weights Empirical observations of growth rates indicate that F I (g), respectively; t is time in days from initial to final fish cutthroat trout do not grow as fast as commercial stocks weights, and °C is water temperature degrees Celsius. Once of rainbow trout and that there is considerable variation TGC is known, growth can be predicted by the following; in growth rate among different cutthroat trout subspecies 1/3 3 and strains. • WF = {WI + Σ[(TGC/100)(°C)(days)]}

5 Growth rate

Temperature

Figure 4. Classic bell-shaped growth-temperature curve.

Thermal growth coefficient values and growth rate are head feeds with high protein-to-lipid ratios provided dependent on species, strain, nutrition, husbandry, and the greatest growth. This is also true for Snake River other factors. It is necessary to determine the specific TGC cutthroat trout grown to market size (Figure 6). An value for a given production system using previous growth on-farm demonstration trial (June 2017–March 2018) and water temperature records. compared the performance of Snake River cutthroat trout fed either a commercial steelhead feed or an experimental Comparing Rainbow and Cutthroat feed (Table 2) based on cutthroat trout performance in Trout Performance laboratory experiments evaluating dietary protein to The mean TGC calculated for rainbow trout grown in dietary lipid ratios, lysine requirement, and vitamin and North Carolina, Idaho, and Pennsylvania from a yield mineral supplementation (Table 3). Snake River cutthroat verification study conducted during 2004–2005 was 0.16 trout fed the experimental feed grew significantly larger and is comparable to previously reported values of 0.15 and than fish fed commercial steelhead feed (Figure 7). The 0.17. In contrast, a good performing strain of Snake River thermal growth coefficient for fish fed experimental feed cutthroat trout grown under variable water temperatures was 0.137 and 0.127 for fish fed commercial steelhead feed. at a salmonid farm had an average TGC of 0.132. Fish grew The experimental feed had higher levels of crude protein from 33 g (13.7 fish per pound) to 359 g (1.3 fish per pound) and lipid than the commercial steelhead feed (Table 4). in 251 days. Under laboratory conditions and a constant Over the 251-day grow-out period, water temperatures water temperature of 14°C, the same strain of Snake River ranged from 9.5 to 14°C (49 – 57°F). cutthroat had a TGC of 0.152. This experiment was 63 days Average weight of the Snake River cutthroat trout at in length and the fish grew from 20 g (22.7 fish per pound) harvest was 343 g (1.3 fish/lb.) and 374 g (1.2 fish/lb.) for to 66 g (6.9 fish per pound). In general, smaller cutthroat fish fed the commercial steelhead and experimental feeds, trout have a higher potential for growth than larger respectively. Fish size at harvest for all fish ranged from cutthroat trout proportionate to their size. Fish growth 92 g (4.9 fish/lb.) to 699 g (0.65 fish/lb.). About 5 months during early rearing can be characterized as exponential after the fish were stocked, precocious males with flowing (Figure 5). milt were observed during all subsequent sampling events. Previous work with fry and fingerling cutthroat trout The precocious males were smaller relative to the sample demonstrated that premium formulations of trout or steel- population and much darker in coloration, with fewer

6 spots. The percentage of precocious males that were producers in the western U.S. is the lack of information for sampled monthly from December 2017 through March specific feeds for cutthroat trout. Use of regular salmonid 2018 ranged from 5.5 to 17%. The use of all-female production feeds may result in lower growth rates and (Figure 8) or triploid cutthroat trout may be warranted higher feed conversion ratios. To improve the efficiency of if precocious males become too numerous or interfere cutthroat trout production, the effects of diet (includ- with production and marketing goals. ing pellet type and commercial vs. experimental feeds) and A challenge facing growers of commercial cutthroat diet formulation (including lysine, digestible protein and trout for the recreational fish stocking market and for feed energy, and vitamin/mineral levels) on the performance of

Gonad development Weight

Fingerling Linear to Maturity “curve” phase

Hatchery Production – Phase - Incubation and Time early rearing

Figure 5. Sigmoid growth curve. Based on Fish Hatchery Management, Second Edition, Gary Wedemeyer, editor.

BOX 1. CALCULATING THERMAL GROWTH COEFFICIENT

This example uses data collected from a commercial farm. Snake River cutthroat trout averaged 33 g when stocked and averaged 359 g when harvested 251 days later.

Water temperatures varied over the 251 days: 58 days at 9.5°C; 33 days at 10.1°C; 34 days at 12°C; 65 days at 12.5°C; 28 days at 13.6°C and 33 days at 14°C.

TGC = (359 g1/3 – 33 g1/3) ÷ [(58×9.5)+(33×10.1)+(34×12)+(65×12.5)+(28×13.6)+(33×14)] × 100 = 0.132

7 Photo credit: Gary Fornshell Figure 6. Market-size Snake River cutthroat trout.

juvenile cutthroat trout under laboratory and production Table 2. Experimental cutthroat trout feed conditions were evaluated. In summary: formulation (as-fed basis). • Empirical observations of cutthroat trout growth rates indicate that cutthroat trout do not grow as fast as INGREDIENTS (%) TEST DIET commercial stocks of rainbow trout. • Previous research and this study indicate Snake River Fish meal, sardine 32.00 cutthroat grow much faster than Yellowstone and Poultry byproduct meal, hi-pro 12.00 Westslope strains, and there are growth differences Blood meal spray dried 3.00 amongst Snake River cutthroat trout strains. Growers meal 2.00 should carefully select the strains of cutthroat trout Corn protein concentrate, 75% CP 6.70 to optimize performance. Soy protein concentrate, Profine VF 3.37 • When fed the same formulation, cutthroat trout Soybean meal, dehulled and perform equally well on floating or sinking pelleted solvent extracted 2.00 feeds. Wheat gluten meal 1.25 • Cutthroat trout growth rates are highest and feed Wheat flour 23.00 conversion ratios lowest when the trout are fed feeds DL-methionine 0.29 with high protein-to-lipid ratios. Cutthroat fed L-Lysine HCl 0.67 commercial salmonid feeds such as premium trout and Dicalcium phosphate 0.30 steelhead feeds performed well. The experimental feed Trace mineral mix, Trout Nutrition 0.10 formulation (Tables 2 and 3) is an open-formula. • Given the limited supply of cutthroat trout relative to Vitamin Premix, ARS 702 1.00 the more common rainbow trout, and their coloration, Choline chloride (60%) 0.60 cutthroat trout, when viewed as a “boutique species”, Stay C (Vitamin C, 35%) 0.20 are potentially more valuable for the recreational Fish oil 11.52 stocking market than rainbow trout. Total 100.00

8 Table 3. Calculated constituent values of experimental feed formulation.

CALCULATED CALCULATED VALUES VALUES

Dry Matter (%) 92.12 Valine (%) 2.32 Protein (%) 45.33 Taurine (%) 0.24 Fat (%) 16.52 Calcium (%) 2.03 Crude fiber (%) 0.95 Phosphorus (%) 1.35 Ash (%) 8.90 Sodium (%) 0.16 Gross energy (kcal/kg) 4843 Chlorine (%) 0.16 Digestible protein (%) 39.80 Potassium (%) 0.37 Digestible energy (kcal/kg) 4080 Magnesium (%) 0.09 Arginine (%) 2.56 Sulfur (%) 0.33 Histidine (%) 1.19 Copper (mg/kg) 11.60 Isoleucine (%) 1.80 Iron (mg/kg) 219 Leucine (%) 3.82 Manganese (mg/kg) 19.85 Lysine (%) 3.40 Selenium (mg/kg) 0.78 Methionine (%) 1.28 Zinc (mg/kg) 100 Cystine (%) 0.55 Digestible phosphorus (%) 0.70 Phenylalanine (%) 2.03 Sum n3 (%) 2.75 Tyrosine (%) 1.30 Sum n3 LC- PUFA (%) 2.40 Threonine (%) 1.69 Sum n6 (%) 0.35 Tryptophan (%) 0.48

400

350 Commercial steelhead feed 300 Experimental feed 250

200 Grams 150

100

50

0 6/28/17 7/27/17 8/29/17 9/26/17 11/1/17 12/5/17 1/3/18 2/2/18 3/6/18

Figure 7. Growth of Snake River cutthroat trout under production conditions fed two diets. Data points indicate sampling dates.

9 Table 4. Proximate composition of the diets.

PERCENT WET WEIGHT EXPERIMENTAL COMMERCIAL STEELHEAD

Moisture 3.9 8.0 Crude Protein 49.4 46.4 Crude Fat 17.3 14.7 Ash 9.6 6.6 Gross Energy (MJ/kg) 22.0 21.5

Photo credit: Gary Fornshell Figure 8. Female Snake River cutthroat trout.

Suggested Readings Ham, BR, CA Myrick, FT Barrows, CJ Yeoman, GC Duff, Deisenroth, DB, CA Bond and JB Loomis. 2012. The MG Maskill, and WM Sealey. 2015. Feed characteristics economic contribution of the private, recreation-based alter growth efficiency of cutthroat trout. Journal of aquaculture industry in the Western United States. Fish and Wildlife Management. 6(1):83–91. Aquaculture Economics & Management. 16 (1):1–21. Owens, CE, WM Sealey, ZB Conley, G Fornshell, and Fornshell, G and C Myrick. 2014. Early rearing of CA Myrick. 2017. Evaluating dietary impacts of cutthroat trout. Western Regional Aquaculture commercial-type diets on the growth of Snake River Center Publication, University of , cutthroat trout (Oncorhynchus clarkii behnkei). Seattle, Washington. Aquaculture 480:77–82. Gatlin, DM, III. Principles of fish nutrition. Southern Piper, RG and coauthors. 1982. Fish hatchery management, Regional Aquaculture Center publication 5003, July 1st edition. U.S. Fish and Wildlife Service, Washington, 2010. DC, USA.

10 Acknowledgments This work was supported by the Western Regional Aquaculture Center [grants #2012-38500-19657 and #2014-38500-22309] from the United States Department of Agriculture National Institute of Food and Agri- culture.

We thank Travis Krebs and his crew at Black Canyon Trout Farm for their most generous support and use of facilities for the demonstra- tion trial. We also thank the following individuals: David Brock, Eli Gough, Jeremy Liley, Biswamitra Patro, Jackie Zimmerman. This project could not have been completed without help from and use of facilities at Colorado State University, U.S. Fish and Wildlife Service Bozeman Fish Technology Center and University of Idaho Hagerman Fish Culture Experiment Station.

Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by USDA-NIFA Western Re- gional Aquaculture Center.

Photo credit: Gary Fornshell

11 The Western Regional Aquaculture Center (WRAC) is one of five centers in the United States. Developed to take advantage of the best aquaculture science, educational skills, and facilities within a twelve-state area, WRAC works to enhance viable and profitable commercial aquaculture production in the U.S. for the benefit of producers, consumers, and the American economy.

To learn more about WRAC, go to the website at depts.washington.edu/wracuw.

Contact WRAC at: Western Regional Aquaculture Center School of Aquatic and Fishery Sciences University of Washington Box 355020 Seattle, WA 98195-5020

phone: 206-685-2479 email: [email protected]

Photo credit: iStock.com/Michael Svoboda 12